Method for producing slurry composition

Abstract

The present invention provides a method for producing a slurry composition which realizes excellent dispersibility through simple steps and can maintain high dispersibility over a long term. In addition, the present invention provides a slurry composition produced using this method. The present invention provides a method for producing a slurry composition containing an inorganic powder, a polyvinyl acetal resin, and an organic solvent. The method contains the steps of mixing an inorganic powder, a mixed polyvinyl acetal resin (A) and an organic solvent (i) to prepare an inorganic dispersion; mixing a polyvinyl acetal resin (B) and an organic solvent (ii) to prepare a resin solution; and adding the resin solution to the inorganic dispersion.

The invention claimed is: 
     
       1. A method for producing a slurry composition that contains an inorganic powder, a polyvinyl acetal resin, and an organic solvent, the method comprising the steps of:
 mixing an inorganic powder, a mixed polyvinyl acetal resin (A) and one or more organic solvents to prepare an inorganic dispersion; 
 mixing a polyvinyl acetal resin (B) and one or more organic solvents to prepare a resin solution; and 
 adding the resin solution to the inorganic dispersion, 
 the mixed polyvinyl acetal resin (A) including a polyvinyl acetal resin (a1) having a hydroxy group content of 20 to 40 mol % and a polyvinyl acetal resin (a2) having a polymerization degree of 200 to 600 and a hydroxy group content of 28 to 60 mol %, 
 the polyvinyl acetal resin (a1) and the polyvinyl acetal resin (a2) being in a relation represented by the following formula (1):
     Y−X≧ 5  (1)
 
 
 
       wherein X represents the hydroxy group content (mol %) in the polyvinyl acetal resin (a1), and Y represents the hydroxy group content (mol %) in the polyvinyl acetal resin (a2),
 the polyvinyl acetal resin (B) having a polymerization degree of 800 to 4200, and 
 the amount of the mixed polyvinyl acetal resin (A) used in the step of preparation of the inorganic dispersion being 0.1 to 20 parts by weight relative to 100 parts by weight of the inorganic powder. 
 
     
     
       2. The method for producing a slurry composition according to  claim 1 ,
 wherein the polyvinyl acetal resin (a1) has a polymerization degree of 20 to 450. 
 
     
     
       3. The method for producing a slurry composition according to  claim 1 ,
 wherein the polyvinyl acetal resin (a2) comprises an anionic group. 
 
     
     
       4. The method for producing a slurry composition according to  claim 1 ,
 wherein the polyvinyl acetal resin (B) has a hydroxy group content of 22 to 42 mol %. 
 
     
     
       5. The method for producing a slurry composition according to  claim 1 ,
 wherein the one or more organic solvents are each mixed solvents comprising ethanol and toluene.